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union.go
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union.go
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// Copyright 2015 The Cockroach Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
// implied. See the License for the specific language governing
// permissions and limitations under the License.
//
// Author: Peter Mattis (peter@cockroachlabs.com)
// This code was derived from https://github.com/youtube/vitess.
//
// Copyright 2012, Google Inc. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file
package parser
import (
"bytes"
"fmt"
)
// UnionClause represents a UNION statement.
type UnionClause struct {
Type UnionType
Left, Right *Select
All bool
}
// UnionType represents one of the three set operations in sql.
type UnionType int
// Union.Type
const (
UnionOp UnionType = iota
IntersectOp
ExceptOp
)
var unionTypeName = [...]string{
UnionOp: "UNION",
IntersectOp: "INTERSECT",
ExceptOp: "EXCEPT",
}
func (i UnionType) String() string {
if i < 0 || i > UnionType(len(unionTypeName)-1) {
return fmt.Sprintf("UnionType(%d)", i)
}
return unionTypeName[i]
}
// Format implements the NodeFormatter interface.
func (node *UnionClause) Format(buf *bytes.Buffer, f FmtFlags) {
FormatNode(buf, f, node.Left)
buf.WriteByte(' ')
buf.WriteString(node.Type.String())
if node.All {
buf.WriteString(" ALL")
}
buf.WriteByte(' ')
FormatNode(buf, f, node.Right)
}